1. Field of the Invention
The present invention relates generally to identification and/or recognition systems, such as supply chain management systems and radio frequency identification systems, which are useful in tracking items, inventory and the like, and in particular, to an intelligent system for tracking and reporting the items, methods and systems for nesting differing radio frequencies and antennae, and unique arrangements in the field of RFID tags, readers and associated systems.
2. Description of the Related Art
There are presently logistical systems for use in connection with large corporate and governmental entities, and these systems must be capable of moving large amounts of material, equipment, ammunition, pre-packaged service modules, products, objects, goods and other items. The logistics of this effort require a system that can manage the movement of goods from supplier-to-consolidation point, shore-to-ship, ship-to-ship, ship-to-shore, shore-to-inland theatres of operations, and from a point of origin to various desired destinations and locations. Accordingly, such a supply chain management system must be designed to allow for real-time accountability, Total Asset Visibility (TAV), and in some applications, rapid deployment and In-transit Visibility (ITV).
Radio frequency identification (RFID) is a non-contact, proximity-based, automatic identification and information technology that does not require manual scanning. An RFID transponder (referred to as an “RFID tag” or “tag”), RFID interrogator (referred to as a “reader”) and attached antenna are the main components of any RFID system. The tag is normally attached to an item to be identified and communications occur via over-air protocols, securely transmitting data to central processing software. An RFID transponder normally consists of a silicon chip (EEPROM) attached to an etched antenna. In operation, as the tag passes through the field, it is activated and, depending on the command of the reader, when the tag is commanded to send its stored information over the air, it is received by the Interrogator Antenna and then forwarded to the RFID Reader to decode the Radio Frequency Signal. Typically, the RFID Reader is hooked up to an Information System backbone, to which it transmits the information from the tag.
According to the prior art, the silicon chip is composed of an RF to DC power conversion component, a digital component for storage and processing of the ID number, and an RF transmitter. Other components may be included to enable frequency hopping schemes, amplification of the output signal, and other additional features. The antenna on the transponder is then externally powered by an RFID interrogator and in sequence transmits the information from the chip through the air to the interrogator.
The tags come in a variety of forms for use in different environments, from fingernail size to 8.5×11 inches. The size of the tag can affect its read ranges, and the antenna determines the size of the tag, occupying more than 95% of a given transponder. The frequency of the antenna is indirectly proportional to the size of the antenna, therefore, the use of higher frequencies can enable smaller antennas to be used. Another antenna characteristic that can greatly affect the size of an antenna is its wavelength. Due to the lack of space on a tag, a ¼ wavelength is usually used. If transmission distance is more important than the tag size, then a ½ wavelength can be used. Interrogator antennae come in many shapes and sizes, which also affect the read-range and pick up rate.
Unlike the bar code, the RFID tag does not have to be in line-of-sight in order to be read. Additionally RFID provides several advantages over existing methods for identification. First, no manual scanning or data entry is required to identify the object for processing. The processing occurs automatically. Second, multiple items can be read via a single scan. RFID is much more durable than bar codes. Because of its non-line-of-sight nature, RFID labels can be read when covered by dirt or grease, or scratched.
Finally, one substantial advantage of RFID technology is its read/write capability and its storage capacity. Unlike the bar code, from which only a static “license plate” number can be read, information can be written to the 96 b-2000 b (2 k) chip embedded in the RFID tag. This enables the tag to act as a local, portable database that travels with the item. This capability allows much less complex and inhibitive system architectures to be designed, as an interface into a master database is not required with every read.
The main RFID hardware components consist of readers and tags. Several types of RFID readers exist, from built-in and fixed to mobile and handheld, that work with different radio frequencies, from low frequency to microwave. RFID readers are connected to enterprise applications like ERP and SCM through middleware. RFID readers first read the data of the RFID tag (such as an Electronic Product Code (EPC)) and also read any additional data such as product description and expiration date. Once this data is collected, the software in the reader can validate the data via a back-end system.
An added layer of difficulty arises from the use of various RFID frequencies. Globally, there are many regulatory bodies that are responsible for frequency standards, such as the FCC in the US; ERO, CEPT, and ETSI in Europe; MPHPT in Japan; and the Ministry of Information Industry in China. RFID technology uses six main frequencies. The low frequency (125 KHz to 134 KHz) is the most mature band in use for RFID, but is limited by its short range, which makes it hard to use for unguided moveable objects like pallets and cases. High Frequency (HF, 13.56 MHz) is used mainly in RFID readers. High Frequency has been used extensively in the contactless smart card arena and has been the choice of many systems for shorter range RFID. It is very appropriate for item-level tags. This frequency only works for distances of less than one meter but it has global regulation that is almost identical, making it a great choice for global commerce. Ultra-High Frequency (UHF, 860 MHz to 960 MHz) is available for use in pallet and case scanning. UHF works well at distances of three to five meters. However, UHF is limited by restrictions from different countries, which forces the reader manufacturers to produce region-specific readers and makes certification necessary on a per region basis. The other frequency band of interest is the 433 MHz band where many of the Active RFID systems operate.
There is an overwhelming need for international coordination of RFID tags and readers. The different international frequency spectrum makes it impossible to mark an object with one RFID tag and use that tag at its international destination with a different acceptable frequency. Presently, a passive tag needs to be placed on an object for a corresponding, accepted frequency associated with each interrogation point in its route. Further, when traveling from international port-to-port the accepted frequencies vary. RFID technology in one country may interfere or violate standards of another country. For example, in many instances, the current RF tags cannot be used after it is outside of its initial country. Still further, active tags either run continuously, in a timed or can be turned on by a second, trigger frequency. Accordingly, a “smart” device is required to deliver this second frequency, and if the device is continuously draining the battery, the lifespan of the battery would be drastically limited.
There are two main types of tags, namely passive tags and active tags. Passive tags are preferred because they do not require a power source and are relatively inexpensive. Passive tags make labeling of inventory simple since they are relatively thin and usually come on adhesive-backed paper. Further, passive tags also provide easy receipt/issue automation and are predominantly available in frequency ranges of 13.56 MHz (high frequency) and 850 to 950 MHz (ultra high frequency). Both are suitable for supply chain management. Active tags are battery powered, bulky and more expensive. They have a limited life expectancy due to the battery charge considerations, however, these tags can read from greater distances and can be set up to monitor external environmental sensors and report the information.
According to the prior art, it has been demonstrated that a supply chain management system operating at a frequency of 13.56 MHz is effective and highly accurate. However, tags operating at this frequency require the reader to be positioned quite close to the tag for effective recognition and identification. Accordingly, tags operating at a 915 MHz frequency are recognizable by a reader positioned at a greater distance from the tag, which allows for a larger scanning area. However, tags operating at this frequency have proven less accurate (producing false “reads”) than tags operating at the 13.56 frequency.
In general, while there are many different inventory and asset management systems available, these systems only provide limited information, which translates into limited asset visibility. Accordingly, these prior art systems and arrangements do not allow for a true end-to-end asset (or inventory) management system that can be used both at a local position, but throughout the world. It is estimated that over 12 million cargo containers enter the United States each year, and over 5% of all container movements in the world develop problems during transit. The containers are misrouted, stolen, damaged or excessively delayed as a result of human error or carelessness (Wall Street Journal, Jan. 05, 2004). A problem of illegal diversion of pallets/containers of goods being shipped to international markets exists. These goods are returning to the United States and other countries on the “Black Market”.
In order to track assets or items on a global level, prior art system rely on the confusing and complex interconnectivity between inventory and tracking systems, which are based on different platforms, different computing systems, and include different terminology and data management. Accordingly, such prior art systems are remit with inaccuracies, inconsistencies, malfunctions, poor communication and result in a severely limited data set regarding the items and assets to be tracked and recognized.